diff --git a/docs/integration/M3H_MAINLINE_RELEASE_SOURCE_CLOSURE_2026-10-24.md b/docs/integration/M3H_MAINLINE_RELEASE_SOURCE_CLOSURE_2026-10-24.md
index 651f26ffd..6d66000ab 100644
--- a/docs/integration/M3H_MAINLINE_RELEASE_SOURCE_CLOSURE_2026-10-24.md
+++ b/docs/integration/M3H_MAINLINE_RELEASE_SOURCE_CLOSURE_2026-10-24.md
@@ -1,5 +1,16 @@
 # M3.H Mainline Source / GitHub Release Closure — 24 October 2026
 
+## Final distribution and hygiene checkpoint — 24 October 2026
+
+- **Mainline regression gate:** the exact merge commit [545bfac](https://github.com/masarray/arstack61850/commit/545bfac104caad8c935633ce8dcfdbf535234115) finished **8/8 SUCCESS** (C++ CI, Security and Evidence, IED Simulator Qt, Embedded Profile, SCL-Assisted Connect/Workbench, BRCB, Naming). This proves that commit, not an unconditional future-main guarantee.
+- **Historical PR queue:** nine SMV/PTP branches and eight divergent Workbench/Browser/IED Simulator PRs were archived **CLOSED UNMERGED**, retaining source references and unresolved acceptance in issues [#300](https://github.com/masarray/arstack61850/issues/300) and [#308](https://github.com/masarray/arstack61850/issues/308). [#309](https://github.com/masarray/arstack61850/pull/309), [#310](https://github.com/masarray/arstack61850/pull/310), and [#311](https://github.com/masarray/arstack61850/pull/311) were merged after CI acceptance for public-code comments, closure ledger, and contributor/security onboarding.
+- **Real installer testing:** [#306](https://github.com/masarray/arstack61850/pull/306) verified Windows Setup downloading through the public PowerShell script plus actual byte/digest equality, and correct Linux installer behavior when AppImage is not published. [#314](https://github.com/masarray/arstack61850/pull/314) runs that public-download acceptance weekly in addition to release events.
+- **Exact-tag Linux candidate:** [#313](https://github.com/masarray/arstack61850/pull/313) merged after [exact-tag Linux CI PASS](https://github.com/masarray/arstack61850/actions/runs/40088688436). It rebuilt Studio using the existing **M3.H tag source**, verified the released ESP32-P4 manifest/Build ID, smoke-tested the packaged AppImage and SHA-256, and stored [artifact #12558167960](https://github.com/masarray/arstack61850/actions/runs/40088688436/artifacts/12558167960) (CI ZIP ~52.2 MB). This candidate is **not** a published Stable Linux download and does not alter the release.
+- **Future release Linux gate:** [#312](https://github.com/masarray/arstack61850/pull/312) integrated optional/manual exact-tag dispatch with latest-Stable verification and a deliberate M3.H freeze. It does not append binaries to immutable M3.H.
+- **M3.H public release:** existing ID `422544367` remains `prerelease=false`, latest, with the **same five original asset IDs and SHA-256**. Source `a922e9bdba4e57a4e88406eb83344455dd8ff142` and tag `processbus-sim-m3h-20261024` are ancestors of current `main`, not necessarily identical to the latest doc/CI main commit.
+- **Administrative/external gates:** GitHub repository About description/homepage/topics are still empty (the connected GitHub API here does not provide a repository-settings mutation). An external deployed portfolio URL has not been established from `masarray/portfolio`; its source wording and build passed but that does not prove publication. These must not be described as verified or mixed into the engineering simulator's successful distribution evidence.
+
+
 ## Decision: Release = Main (DONE)
 
 - **Existing PUBLIC STABLE release:** [processbus-sim-m3h-20261024](https://github.com/masarray/arstack61850/releases/tag/processbus-sim-m3h-20261024), GitHub release ID **422544367**, `draft=false`, `prerelease=false`, latest stable.